Mechanical packers, or packers, are commonly used to inject liquids under pressure into cracked and damaged concrete to fill voids thereby stopping leaks and further degradation of the concrete. The repair compounds injected usually are an epoxy or a polyurethane that set or harden over time in the voids in the damaged concrete. Metallic packers are typically used in medium to high pressure applications where the concrete may be severely damaged while plastic packers are typically used in low pressure applications where the damage to the concrete is less severe.
In many instances, the packer has a feed tube that extends a distance from the concrete structure after the packer is inserted. The packer either remains in the structure, or is removed only after the repair compound has set. One such packer, shown in U.S. Pat. No. 5,476,344 to Nordvall issued on Dec. 19, 1995, discloses a concrete injection mechanism with an expandable end portion. The expandable end portion, which is located in a pre-drilled bore in the concrete, works in conjunction with a non-return valve. As a liquid repair material is forced under pressure into the injection mechanism, the diameter of the expandable end increases before the non-return valve opens to release the pressurized material into the concrete, thus securing the injection mechanism in the bore. However, the feed pipe cannot be disconnected and the outer end removed until the material is allowed to harden, as the repair material would no longer be held under pressure.